Method and device for applying a plurality of threads to a support with the aid of flexible teeth

ABSTRACT

A method and device (1) for causing a plurality of threads (7) to arrive on support (11) so as to obtain a ply (13) while imparting a nonlinear shape to the threads (7). The threads (7) are caused to arrive with controlled speed on a cylindrical drum (2) in rotation around an axis. The threads (7) are imparted the nonlinear shape by means of teeth (5) which are displaced with respect to others, parallel to the axis of rotation. At least some of these teeth are flexible between a free end in contact with a thread (7) and an anchoring zone. Plies (13) obtained with this method or device, these plies being used for instance in a tire.

BACKGROUND OF THE INVENTION

The present invention relates to devices and methods for applyingthreads to supports, in particular supports of plastic or rubber, thesedevices and methods making it possible, for example, to producereinforcement plies, in particular reinforcement plies for tires. Theinvention relates, in particular, to methods and devices which make itpossible to apply threads to a support while imparting a nonrectilinearshape to them, for instance a sinuous shape.

Devices which make it possible to apply threads to a support whileimparting a sinuous shape to them are described, for instance, in thefollowing patents or patent applications: FR 2 042 859, FR 2 325 497, FR2 501 126, SU 704, 816, WO 81/1151.

These devices have at least one of the following drawbacks:

complex character of the devices, giving rise to frequent breakdowns ormaking costly and frequent maintenance necessary;

a lack of precision in the laying of the threads, so that the pliesobtained have a heterogeneous geometry and therefore present physicalproperties which vary in accordance with their length.

Application EP-A 318 791 describes a device for applying threads to asupport using two clamps, a front clamp and a rear clamp as seen in thedirection of advance of the support and of the threads, the devicecomprising means making it possible to open and close the clamps andmeans for displacing the rear clamp along the direction of advance oralong a direction opposite to the direction of advance, as well as meansfor displacing the threads in transverse directions. The devicedescribed in said application EP-A-318 791 makes it possible to lay thethreads with great precision, but the speed of laying is relatively slowdue to the complex succession of movements of the clamps, which requirestops of the support upon transverse movements of the threads beforethey are applied to the support and upon the application of the threadsto the support.

SUMMARY OF THE INVENTION

The object of the invention is to overcome the drawbacks describedabove.

Accordingly, the method of the invention for applying a plurality ofthreads to at least one support so as to obtain at least one ply whileimparting a nonlinear shape to the threads is characterized by thefollowing features:

(a) each of the threads is fed with a controlled speed onto acylindrical drum rotating around an axis;

(b) the threads are imparted the nonrectilinear shape by means of teethwhich are displaced with respect to each other parallel to the axis ofrotation;

(c) at least some of these teeth are flexible between a free end, incontact with a thread, and an anchoring zone;

(d) due to the flexibility of the flexible teeth, the amplitude ofdisplacement of each thread, measured parallel to the axis of rotation,is determined by the ratio between the speed of arrival of this threadand the peripheral speed of the drum;

(e) the support or supports are caused to arrive in contact with thedrum and the threads are applied to the support or supports after thethreads have been displaced on the drum;

(f) the ply or plies formed by the support or supports and by thethreads in contact with said support, are removed from the drum.

The invention also concerns a device for applying a plurality of threadsonto at least one support so as to obtain at least one ply, whileimparting to the threads a nonrectilinear shape, the device beingcharacterized by the following features:

(a) it comprises a drum having means making it possible to drive thedrum in rotation around an axis;

(b) it comprises means making it possible to have the threads arrive,each with a controlled speed, onto the drum;

(c) it comprises teeth and means making it possible to displace theseteeth with respect to each other parallel to the axis of rotation, so asto impart the nonrectilinear shape to the threads;

(d) at least some of these teeth are flexible between a free end incontact with a thread and an anchoring zone;

(e) it comprises means making it possible to have the support orsupports arrive in contact with the drum and of applying the threads onthe support or supports after these threads have been displaced;

(f) it comprises means making it possible to remove from the drum theply or plies each formed by the support or supports and by the threadsin contact with said support.

The invention also relates to the plies obtained by the method or devicepreviously described above, as well as articles incorporating theseplies, these articles being, for instance, hoses, membranes, belts, ortires.

The expression "thread" is to be taken in a very broad sense. A threadmay be a "single thread" formed, for instance, of one or more filaments.When the single thread is formed of a single filament, it is referred toas a "monofilament" and when the single thread is formed by severalfilaments, it is referred to as a "multifilament".

A thread may, furthermore, itself be an assembly of single threads. Byway of example, such an assembly is called a "twist" when it is formedby several individual threads combined by a single twisting operation,and such an assembly is referred to as a "cable" when it is formed ofseveral threads, at least one of which is a twist, combined by one ormore twisting operations.

The invention will be easily understood by means of the nonlimitativeexamples which follow and the diagrammatic figures relating to theseexamples.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side elevational view in section of a device in accordancewith the invention;

FIG. 2 shows the device shown in FIG. 1 in profile view, in thedirection of the arrow F shown in FIG. 1., the section of FIG. 1 beingindicated by the lines I--I in FIG. 2;

FIG. 3 is a sectional view of a portion of the device shown in FIGS. 1and 2;

FIG. 4 shows, in partial section, the portion of the device shown inFIG. 3 in the two conditions designated 4A and 4B, the section of FIG. 4being diagrammatically indicated by the lines IV--IV in FIG. 3;

FIGS. 5 and 6 each show an arrangement of the threads on the drum of thedevice shown in FIGS. 1 and 2;

FIG. 7 shows, in section, a portion of another device in accordance withthe invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 show a device 1 in accordance with the invention. Thisdevice 1 has a drum 2 of generally cylindrical shape and a motor 3 whichmakes it possible to drive the drum 2 in rotation around the axis xx'.FIG. 1 is a section perpendicular to the axis xx', which is representedby the letter x in said figure, and FIG. 2 is a profile view, seen inthe direction of the arrow F in FIG. 1, of the device 1.

The rotation of the drum 2 is diagrammatically indicated by the arrow F2in FIG. 1. The device 1 comprises rows 4 of teeth 5. Every other row 4,designated 4A, has its teeth 5A fixed, while the other alternate rows,designated 4B, have flexible teeth 5B, the number of flexible teeth 5Bof any row 4B being the same for all the rows 4B and equal to the numberof fixed teeth 5A of any row 4A, which is also the same for all the rows4A. The fixed teeth 5A are fastened directly on the drum 2, the rows 4Aof these teeth being parallel to the axis xx' and disposed alonggeneratrices of the cylinder 2. The movable teeth 5B are arranged ingrooves 6 in the drum 2, one groove 6 for each row 4B, each of thesegrooves 6 being directed parallel to the axis xx' and along a generatrixof the cylinder 2. The means for the displacement of the movable teeth5B are not shown in FIGS. 1 and 2, and will be described in greaterdetail below.

Threads 7 are caused to arrive in contact with the drum 2 and the teeth5 of the rows 4. For this, the threads 7 come from a feed devicecomprising, for instance, a creel 8 and a capstan 9. Each of the threads7 arrives on the drum 2 with a controlled speed. The place where thethreads 7 arrive in contact with the drum 2 is indicated by A. At thisplace A, the fixed teeth 5A and the movable teeth 5B of rows 4A, 4B aredisposed substantially in planes P perpendicular to the axis xx', theseplanes being the same for the fixed teeth 5A and the movable teeth 5B.For purposes of simplification, FIG. 2 shows only two threads 7 and asingle plane P (shown in dashed line). As a result of the orientation ofthe teeth 5 in planes P, each thread 7 contacts the drum 2 substantiallyparallel to the planes P along a circle of axis xx' between pairs offixed teeth 5A and between pairs of movable teeth 5B.

Upon the rotation of the drum 2, starting from A, the movable teeth 5Bare displaced in the direction of the arrows F5, which causes adeformation of the threads driven by the teeth 5B and these threads 7are no longer circular on the drum 2 but are given a sinuous shape, therows 4 being driven in rotation around the axis xx' with the sameangular speed as the drum 2.

After their displacement, the threads 7 arrive at the roller 10 whichmakes it possible to apply the support 11 by calendering to the drum 2.The means for feeding the roller 10 with support 11 are known and arenot shown in the drawing for purposes of simplification. The roller 10has grooves 12 which are directed along the generatrices of the roller10. The arrangement of the grooves 12 on the roller 10 is such that atthe place where the roller 10 applies the support 11 onto the drum 2,the teeth 5A, 5B pass through the support 11 and are disposed in thegrooves 12, without touching the roller 10. This place is marked B inFIG. 1. For simplicity in the drawing, the arrival of the support 11 isnot shown in FIG. 2 and a single groove 12 is shown in FIGS. 1 and 2.

The ply 13 formed by the support 11 and the sinusoidal threads 7 appliedon said support then passes between the roller 10 and an extractionroller 14, and the ply 13 is wound on the spool 15, driven by the motor16. The axes of the rollers 10, 14 and of the spool 15 are notreferenced on the drawing and are parallel to the axis xx'.

The advances of the threads 7, of the support 11 and of the ply 13 areindicated by the arrows F7, F11 and F13, respectively, in FIG. 1.

FIGS. 3 and 4 show the operation of the movable teeth 5B.

FIG. 3 shows a portion of the device 1 comprising a row 4B of movableteeth 5B as well as an adjacent row 4A of fixed teeth 5A and thecorresponding portion of the drum 2. The section of FIG. 3 is takenperpendicular to the axis xx', as shown in FIG. 1.

FIG. 4 shows the row 4B corresponding to FIG. 3, FIG. 4 being a partialsection along a plane containing the axis xx', the section of FIG. 4being indicated diagrammatically by the lines IV--IV in FIG. 3. ThisFIG. 4 represents two conditions, marked 4A and 4B. Each flexible tooth5B comprises a free end 5-1, intended to come in contact with a thread 7and an anchoring zone 5-2. All the anchoring zones 5-2 of row 4B areattached rigidly to a part 17, said part 17 and the teeth 5B forming ablock of comb shape, formed, for instance, in a single piece by moldinga plastic material or by machining a metallic material. The teeth 5B areflexible between their free end 5-1 and their anchoring zone 5-2, theflexing of the teeth 5B taking place substantially along a plane passingthrough the axis xx' that is to say the plane of FIG. 4 The rows of ends5-1 and the rows of fixed teeth 5A are disposed substantially alonggeneratrices of the cylinder 2. For simplicity in the drawing, only twothreads 7 are shown in FIG. 4.

The part 17 is firmly attached to a bar 18 which can come into contactwith a cam 19 due to a return spring 20. For the simplicity of FIG. 4,the part 17, the bar 18, and the teeth 5B have not been shown insection. The part 4A of FIG. 4 represents the position of the row 4Bwhen the cam 19 is not exerting any action on the bar 18. In this case,the teeth 5B have an unbent position, each being substantially in apreviously defined plane P containing at least one tooth 5B. The teeth5B are in this position when they receive the threads 7 at A.

The part 4B of FIG. 4 represents the position of the row 4B when the cam19 exerts action on the bar 18. In this case, the teeth 5B are displacedin the direction of the arrow F5, parallel to the axis xx', andtherefore in the plane of FIG. 4. Furthermore, a flexing of the teeth 5Btakes place, the threads 7 limiting the stroke of the free ends 5-1 ofthe teeth 5B to a value less than the stroke of their anchoring zone5-2. The stroke of the anchoring zone 5-2 of all the teeth 5B is thesame for the entire row 4B, this stroke being marked "d" in FIG. 4B. Thebend of each tooth 5B is marked "f", only one of these bends being shownin FIG. 4B. The stroke "c" of the end 5-1 of a tooth 5B, in thedirection of the arrow F5 is therefore equal to d-f. The teeth 5B assumethis position after they have received the threads 7 at A and until theapplication of the support 11 at B. The arrangement is identical to thatwhich has been described for all the rows 4B of movable teeth 5B.

Each of FIGS. 5 and 6 shows a portion of five threads 7 arranged on thedrum 2 upon the production of the ply 13, at the place B, that is to sayat the time when the support 11 is applied against the threads 7. InFIGS. 5 and 6, the longitudinal direction, that is to say the averagedirection of the threads 7, corresponding to circles of the drum 2 ofaxis xx', is represented by F1 and the transverse direction,corresponding to the generatrices of the drum 2, is represented by thearrow Ft.

The threads 7 of FIGS. 5 and 6 all have a sinuous shape, for example aperiodic sinuous shape. By definition, the ratio T of a thread 7 is theratio between, on the one hand, the length of a portion of threadbrought to a linear position and, on the other hand, the linear distancebetween the ends of said portion when the thread has a sinuous shape. InFIGS. 5 and 6 each thread 7 has substantially rectilinear sectionsbetween two successive teeth 5A, 5B in contact with said thread. Inthese FIGS. 5 and 6, the length of thread 7 between one tooth 5A and afollowing tooth 5B is represented by "a" and the distance between twosuccessive teeth 5A is represented by "2b", "b" representing thedistance between two successive rows 4A, 4B, this distance being, forinstance, constant over the entire periphery of the drum 2. In thiscase, one therefore has T=a/b. The invention applies to the case thatthe threads 7 have sinuous shapes which do not have a linear segment, Thaving always the same definition. For any given thread 7, T is equal tothe ratio between the speed with which this thread 7 arrives on the drum2 and the peripheral speed of rotation of the drum 2, the thread 7 beingassumed nonstretchable.

In FIG. 5, the strokes "c" of the free ends 5-1 are all identical, sincethe threads 7 have all been introduced onto the drum 2 with the samespeed, the ratio T is then the same for all the threads 7.

In FIG. 6, the strokes "c" of the free ends 5-1 are different from onethread to the other since these threads 7 have all been introduced ontothe drum 2 with different speeds. The ratio T, therefore, varies fromone thread 7 to the other. FIG. 4B corresponds to such an embodiment,the bend f varying from one thread 7 to the other.

On the finished ply 13, the threads 7 retain substantially thearrangement which they had just before the withdrawal of the teeth 5 dueto the rotation of the drum 2, that is to say the peaks S of the sinuouspaths of the threads 7 correspond substantially to the previous positionof the teeth 5A, 5B (FIGS. 5 and 6).

It is necessary to control the speed with which the threads 7 aredelivered onto the drum 2. This control can be effected, for instance,by two methods. In a first method, a single capstan 9 is used, each rollof the capstan having as many rollers as there are different speeds forthe threads 7. In order to modify the law of variation of the speeds ofthe threads 7, it is sufficient to modify the stacking of the rollers onthe fluted shafts of the drums. These fluted shafts and the drum 2 aredriven, for instance, by a single motor with a kinematic chain withoutslippage using, for instance, gears, chains or notched belts. One thusmechanically assures the ratio of the speeds between the threads 7 andthe drum 2.

In a second method, as many capstans 9 are used as there are differentspeeds, the speed varying therefore from one capstan to the next, thesecapstans being driven separately with, for each of them, control of thespeed as a function of the peripheral speed of the drum. This lattermethod is at present more expensive that the preceding one, but itresults in greater flexibility.

The two methods mentioned above are known and they have not been shownon the drawing for purposes of simplification.

It is possible to vary the speed for the groups of threads, rather thanthread to thread, in order to simplify the development, that is to say,in the first method, each roller then corresponds to a group of threadshaving the same speed of introduction onto the drum 2 and, in the secondmethod, each capstan corresponds to such a group of threads. In thiscase, it may be advantageous to have, in each row 4B, a single forkedtooth 5B per group of threads, said tooth having as many free ends 5-1as there are threads 7 per group.

The invention provides the following advantages:

One operates continuously, without stopping the rotation of the drum 2,which makes it possible to have high speeds which can, for instance,reach or exceed 5 meters/min.

A ply 13 is obtained, the threads 7 of which are disposed with greatuniformity on the support 11. The ratio T of a thread 7 is determined,as previously mentioned, by the ratio between the speed of arrival ofthis thread 7 on the drum 2 and the peripheral speed of said drum. As itis possible to impose desired values for this ratio, the ratio T can becontrolled with great precision. The fluctuation of the ratio T of eachthread is, for instance, 0.5%, plus or minus with respect to any nominalvalue T_(n), selected for this thread.

The nominal ratio T_(n) may vary within wide limits from one thread 7 tothe other of the ply 13; this ratio which is greater than 1 can, forinstance, go up to 3.

Due to the great precision of the ratios T for the ply 13, the latter ischaracterized by well-defined mechanical properties in the article inwhich it is incorporated, for instance a tire, even if said articleundergoes shaping upon its manufacture.

The variation in the ratio T_(n) is very easy to obtain; this ratio cantherefore be rapidly changed upon manufacture so as to have a variationof T_(n) not only in the transverse direction, that is to say parallelto the axis xx', but also in the longitudinal direction, for instanceupon adjustments of the device, that is to say in the direction ofpassage of the thread 7 and of the support 11.

In general, the threads 7 adhere sufficiently to the support 11 in orderto separate themselves spontaneously from the teeth 5 at the place B.However, it may be useful to make the fixed teeth 5A and the movableteeth 5B retractable, for instance with an eccentric system such asshown in FIG. 7. A hollow eccentric 21 surrounds the drum 2, itsdiameter being smaller than that of the eccentric 21. This eccentricturns around its axis, represented by z in FIG. 7, while the drum 2turns around its axis xx', represented by x, different from z, FIG. 7being a section perpendicular to the axes x, z, which are parallel. Theeccentric 21 and the drum 2 turn on their axes with the same angularvelocity. The fixed or movable teeth 5 protrude extensively from thedrum 2 and can pass through the eccentric 21 due to cuts 22 machined inthe latter, parallel to the axes x, z. By properly arranging the axis z,the result can be obtained that the teeth 5 end up by retracting intothe cuts 22 precisely at the place where the support 11 is applied tothe threads 7, that is to say at the place B. This makes it possible tofree the threads 7, which therefore do not run the risk of remaininghooked on the teeth 5.

Furthermore, in the embodiment previously described, the passage of thethreads in sinuous position was obtained by the action of a cam, whichcaused the compression of a spring. In another possible embodiment, thispassage can be effected by termination of the action of a cam, causingthe relaxation of a spring.

The ply 13 can be used as reinforcement in articles such as hoses,membranes, belts and tires.

It is possible to do away with the sinusoidal shape of the threads 7upon the shaping of the article in which the ply 13 is used, asdescribed in the aforementioned application EP-A 318 791, or else thissinuous shape can remain, in whole or in part, in the finished article.

The threads 7 are preferably textile threads, the diameter of whichvaries from 0.2 to 4 mm.

The invention also covers cases in which the decrease in the nominalratio T_(n) is reversible, for instance in the case of a membrane formedby a ply in accordance with the invention the support of which iselastic, the deformation of this membrane, under the effect, forinstance, of the pressure of a fluid, causing a decrease in said ratio,but the threads resume their initial ratio T_(n) when the membraneresumes its initial shape. This membrane, made for instance ofvulcanized rubber, can serve, in particular, for the making, shaping orvulcanizing of tires.

Of course, the invention is not limited to the embodiments describedabove.

Thus, in the example previously described, the flexible teeth 5B arethose whose anchoring zones 5-2 are displaced, but one can contemplatecases in which these anchoring zones are fixed while rigid teeth aredisplaced. Cases in which all the teeth are flexible can also becontemplated.

It can also be contemplated that all the teeth, whether rigid orflexible, have driven anchoring zones, for instance some in onedirection and the others in the other direction.

I claim:
 1. A method of applying a plurality of threads to at least onesupport in such a manner as to obtain at least one ply, imparting anonrectilinear shape to the threads, comprising:(a) feeding each of thethreads with a controlled speed onto a cylindrical drum rotating aroundan axis; (b) imparting the nonrectilinear shape to the threads by meansof teeth disposed in rows substantially along generatrices of the drum,some of which rows of teeth are displaced parallel to the axis ofrotation with respect to other rows, at least some of these teeth havinga flexible free end engageable with a thread; (c) determining, due tothe flexibility of the flexible teeth, the amplitude of displacement ofeach thread, measured parallel to the axis of rotation, by controllingthe ratio between the speed of arrival of said thread and the peripheralspeed of the drum; (d) bringing the support or supports in contact withthe drum and applying the threads to the support or supports after thethreads have been displaced on the drum; and (e) removing the ply orplies formed by the support or supports and by the threads in contactwith said support from the drum.
 2. A method according to claim 1, inwhich the free ends of the flexible teeth are disposed along rowsparallel to the axis of rotation of the drum, and in which the drum hasrows of fixed teeth parallel to the axis of rotation of the drum, thenumber of teeth being the same from one row to the next, the rows beingalternately rows of fixed teeth and rows of flexible teeth, the rows offixed teeth and the free ends of the teeth of the rows of flexible teethbeing disposed substantially along generatrices of the cylinder of thedrum.
 3. A method according to claim 2, in which the threads are fed incontact with the drum at a place where corresponding of the fixed andflexible teeth are disposed substantially in planes perpendicular to theaxis of rotation of the drum, these planes being the same for the fixedteeth and the flexible teeth, the threads being disposed parallel tosaid planes between pairs of fixed teeth and pairs of flexible teeth. 4.A method according to claim 1, in which the threads are imparted asinuous shape on the drum and the support or supports are caused toarrive in contact with the drum at a place where the threads haveacquired substantially their final sinuous shape on the drum.
 5. Amethod according to claim 4, in which the sinuous shape is periodic. 6.A method according to claim 1, in which the threads are caused to arriveon the drum with the same speed for all the threads.
 7. A methodaccording to claim 1, in which the threads are caused to arrive on thedrum with different speeds for different threads or groups of threads.8. A device for applying a plurality of threads to at least one supportso as to obtain at least one ply, while imparting a nonrectilinear shapeto the threads, the device comprising:(a) a drum with means making itpossible to drive the drum in rotation around an axis; (b) means makingit possible to have each of the threads arrive with a controlled speedonto the drum; (c) teeth disposed in rows substantially alonggeneratrices of the drum and means which make it possible to displaceparallel to the axis of rotation at least some of these rows of teethwith respect to other rows, so as to impart the nonrectilinear shape tothe threads; (d) at least some of these teeth having a flexible free endengageable with a thread the amplitude of the displacement of eachthread being determined, due to the flexibility of the teeth, by theratio between the speed of arrival of said thread and the peripheralspeed of the drum; (e) means which make it possible to have the supportor supports come into contact with the drum and to apply the threads tothe support or supports after said threads have been displaced; and (f)means making it possible to remove from the drum the ply or plies formedby the support or supports and by the threads in contact with saidsupport.
 9. A device according to claim 8, in which the free ends of theflexible teeth are disposed along rows parallel to the axis of rotationof the drum, and in which the drum comprises rows of fixed teethparallel to the axis of rotation of the drum, the number of teeth beingthe same from one row to the next, the rows being alternately rows offixed teeth and rows of flexible teeth, the rows of fixed teeth and thefree ends of the teeth of the rows of flexible teeth being disposedsubstantially along generatrices of the cylinder of the drum.
 10. Adevice according to claim 9, in which the means making it possible tohave the threads arrive on the drum are so arranged that they make itpossible to have the threads arrive in contact with the drum at a placewhere corresponding of the fixed and flexible teeth are disposedsubstantially in planes perpendicular to the axis of rotation of thedrum, these planes being the same for the fixed teeth and the flexibleteeth, the threads being disposed parallel to said planes, between pairsof fixed teeth and pairs of flexible teeth.
 11. A device according toclaim 9, in which the fixed and flexible teeth are so arranged as toimpart the threads a sinuous shape on the drum and in which the meansmaking it possible to have the support or supports arrive in contactwith the drum and to apply the threads to the support or supports are soarranged that the support or supports arrive in contact with the drum ata place where the threads have acquired substantially their finalsinuous shape on the drum.
 12. A device according to claim 11, in whichthe sinuous shape is periodic.
 13. A device according to claim 8, inwhich the means which make it possible to have the threads arrive on thedrum are so arranged that all the threads have the same speed upon theirarrival on the drum.
 14. A device according to claim 8, in which themeans which make it possible to have the threads arrive on the drum areso arranged that the threads, or groups of threads, have differentspeeds upon their arrival on the drum.